1. Field of the Invention
The present invention relates to an information processing apparatus and an information processing method, and more particularly, to an information processing apparatus and an information processing method for carrying out color image correction.
2. Description of the Related Art
In recent years, with the spread of digital cameras and other such image sensing apparatuses and improvements in personal computer performance capabilities, users now have more opportunities to retouch digital images to suit their own preferences. Retouching software applications are now sold by many companies, and users can now easily carry out sophisticated image processing as well. For example, even during image correction it is now common to carry out color correction by trial and error while conducting a test print so as to obtain a print of a desired color tone.
Color correction usually requires a procedure in which multiple corrections are repeated for a plurality of colors. For example, in a case of an image of scenery in which a person is present, first the overall brightness is corrected, then the color of the sky, the color of the leaves, the color of the skin and so forth are sequentially corrected to suit one's preferences, and finally an image having the desired color tone is obtained. There are retouching software applications that have the capability to carry out color correction automatically, but they are not perfect and fine adjustment is required to obtain correction results that accord with individual users' needs.
In addition, it is not unusual that, after carrying out correction of one color, while carrying out correction of another color one wishes to re-correct the corrected color. Specifically, in the example described above, after correcting the color of the sky, suppose the color of the leaves is corrected. At this time, if a balance between the corrected color of the leaves and the previously corrected color of the sky is not to one's liking, one will want to re-correct the color of the sky.
When such a correction process is carried out for colors of a variety of different locations, overall optimization becomes difficult. For example, when the color of the sky is corrected, colors of a comparable color hue are affected, with results that the user does not intend.
A common method of preventing color conversions not intended by the user is to limit the correction subject region by color hue/saturation/brightness and correct only that region. However, even with this method, in order to prevent the problem described above it is necessary to store information on the region subjected to correction. Where there are many converted regions it is in reality difficult to fully store the information, and the problem of color corrections not intended by the user remains.
In addition, when re-correcting a once-corrected portion, it is possible to use an undo function, for example, and to return to a past state. However, depending on the size of the image and the content of the erasure process, the computations required to recover would take time and require an enormous memory.
Japanese Patent Laid-Open No. 2006-121321 discloses a technology that, by having a color-space conversion table for each piece of history data, obtains an image of a past state with less memory than with a method that saves an image each time a correction is carried out.
In the technique described in Japanese Patent Laid-Open No. 2006-121321, it is possible to recover an image of a time in the past by sequentially tracing back through the history of corrections carried out in the past from a newest image. However, when color conversion that is different from before is applied to the recovered image, the color-space conversion tables for the color conversions implemented thereafter become invalid. As a result, in order to reproduce the results of the color conversions modified thereafter it is necessary to recalculate. Where the conversion process requires complex calculations, and the further back in the past the recovery, the time required for these calculations lengthens and the problem of lengthened processing time remains.
Further, the problem of color conversions not intended by the user occurring in color conversions of limited regions is not solved by the method of Japanese Patent Laid-Open No. 2006-121321.